摘要
应用自制的高性能爆裂仪能探测到小秦岭地区脉型金矿微小包裹体的热爆温度,探测到金矿成矿热流体的存在及其活动强度;根据包裹体热爆曲线特征判别岩石的含金性及区分富金矿石和贫金矿石,为金矿找矿与评价提供重要依据。
Xiaoqinling gold deposits are located at the border of Henan and Shanxi provinces, occurring in Archaean metamorphic rocks of Taihua group. The deposits are of vein type consisting of gold, sulphide and quartz. More than thousand Au-bearing veins constitute an important gold field.
There are three types of fluid inclusions in Au-bearing vein. They are CO_2-inclusion, CO_2+H_2O inclusion and H_2O inclusion, with early stage of CO_2 andCO_2 +H_2O inclusions and late stage of CO_2+H_2O and H_2O inclusions. The late stage inclusions distributed along the filled-fissures of the early stage quartz and were trapped during the gold-mineralization.
For the early stage inclusions avevage Th is 300℃, Td is 342℃,while for the late stage inclusions, the Th range is 139—260℃ and Td range 90—265℃.The Td of the natural gold is 261℃.
For the early stage vein quartz the Td curve is of straight line or high temperature single peak type, whereas for the late stage vein quartz it is of medium-low temperature single peak type. If the late stage thermal activity overlapped the early one the decrepitation curves of the straight line type could be replaced by medium -low temperature type, and the high temperature single peak type by the double-peak type.
Au-mineralization quartz veins are involved in the late stage trapping of fluid inclusions, and show a medium-low temperature peak in their Td curves.
The higher the peak,the better the gold-mineralization is and a positive correlation between them could be seen. Based upon lhis fact the gold-bearing nature and the degree of mineralization of an unknown ore might be estimated. The result provides a helpfull criterion for the gold prospection.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
1989年第4期15-21,共7页
Acta Petrologica Sinica
